Process of obtaining dinitroglycerin, &amp;c.



PATENTED FEB. 25, 1908.

F. I. DU PONT. PROCESS OF OBTAININ G DINITROGLYGBRIN, 6m.

APPLICATION FILED SEPT. 11, 1907.

2 SHEETSSHEET 1.

R m w m No. 879,899. PATENTED FEB. 25, 1908.

P. I. DU PONT.

PROCESS OF OBTAINING'DINITROGLYOERIN, 620.

APPLIOATION FILED SBPT.11,1907.

2 SHEETS-SHEET 2.

to proper separation of the dinitrog lycerin rinrran s 'rarns PATENT er sion.

FRANOISI DU PONT, OF WILMINGTON, DELAWARE, ASSIGNOR TO THE E. I. DU FONT DE NEMOURS POWDEROOMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF NEW JERSEY.

Specification of Lettbrs Patent.

Patented 1 50125, 1908.

Application filed ScptemberlL 1907 Serial No. 392,257- I T all whom it may concern:

Be it known that I, Framers I. DU Pour, a citizen of the United States, residing at Wilmington, county of Newcastle, and State 5 of Delaware, have invented a new and use ful Improvement in Processes of Obtaining Dinitroglycerin, &c., of which the following is a full, clear, and exact description, reference being had to "the accompanying drawings, which form a part of this specification.

My invention relates to that class of nitrations where nitric acid alone is used, as, for example, the manufacture of dinitroglyccrin.

It has for its object to neutralize the excess nitric acid with ammonia and thus produce, as a by-product, nitrate of ammonia which itself is a valuable product, and the recovery of the dinitro-glycerin and by-product.

In the manufacture of di-nitro-gl'yceriu,

nitric acid alone is used to produce the nitration. When the nitration has proceeded to the extent oi'forming dinitro-glycerin, ordinarily calcium carbonate or some similar substance is used to neutralize the excess nitric acid. Thiscan be readily used, as the action is without the production of heat or affecting the dinitroglycerin' formed. On the other hand, with this neutralizer calcium nitrate is obtained as a byproduct, which is a valueless product. In like manner with the other neutralizing substances used, a relatively valueless product is also produced.

Nitrate of ammonia is a valuable product. If ammonia be used, in the same manner as 36 calcium carbonate, to neutralize the excess of nitric acid, difliculties arise. Ammonia being a strong base, and nitric acid a strongacid, the reaction is violent, causing heat v and, with di-nitro-glycerimthe consequent 40 decomposition of the dinitrolyceriu. In

my process when I introduce t eammonia, I at thesame time, maintain or. cause the maintenance of the mixture at a tempera-- ture at which the dinitroglycerin will not decompose.

When ammonium hydroxid is used, it is generally necessary or desirable that considerable water should be added with thisammonia hydroxid. This added water prevents the from the solution. I remove this water to an extent which will allow the separation of the 'dlmtroglycerin 1n the following man- Joel. and. recover? of dmitrogryceiin and filterin material.

the by-product, nitrate, oi ammonia: I subject the mixture after neutralization to the' action of heat and a vacuum Dinitroglycerin is quite sensitive to heat, but by the use of a vacuum, theevaporating point of the water is so lowered that the heat necessary to be used is insu'l'licient to afiect the dinitroglycerin. The extent of the vacuum which I use will depend upon .the extent to which the neutralization has been made perfect. neutralization be not complete, the dinitroglycerin in the presence of the remainingacid is far more sensitive to heat than it would he were the neutralization complete and thus such acid not present. The vacuum will also vary or be dependent upon the amount or quantity of the ammonium salt produced in the neutralization.

In my practice of producing dinitroglycerin I exercise great care to produce complete The reason for this is that if, the.

neutralization and under such circumstances I have found that a'vacuum corresponding to a reduction of 28.229 in. of mercury t. 'c.,

Fig. 3 re resents in section a vessel for removing tr e water.

Speaking first of Fig. 1 a is a vessel having a water jacket I) through which Water may be passed in the ordinary and well known mart.

Into this vessel are introduced with the usual precautions the glycerin and nitric acid. Above the bottom of this vessel is a ner filterirn stone 0 or other filtering material.

" is I316 stirrer connected to the shaft 6 re.-

solved in the ordinary manner by means not shown.

f is a pipe which enters vessel (1 below the:

procee ed to theproper extent toform dinitroglycerin, ammonia Water isintroduced, under ressure, through the pipe f, the rate of thewater jacket]; maintains a temperature at which the dinitroglycerin will not be (13-:

When. the nitration has.

The water in composed. As a result, there is produced dinitroglycerin in the presence of some water and nitrate of ammonia in solution. The so-v lution of nitrate of ammonia is then concentrated and dried. There is thus produced a valuable product, nitrate of ammonia, made from the unavoidable excess of nitric acid which it is necessary to employ in the manu facture of the main roduct.

. I do not intendto imit myself to the use of my invention in the manufacture of .dini'tro glycerin, as it can be used with any similar 1 nitration where nitric acid, without sulfuric acid, is used. Further, as shown in Fig. 2,

,where g isthe vessel and 71. the water 'acket, I ,can. eliminate the 'filtering materia .in, the

- bottom, and the pipe f as shown in Fig. 1, and form the stirrer i and stirrer shaft 7' hollow. The stirrer 'i at its ends having outlets and having filtering materialk in the hollow portion of said stirrer. In this case, the ammonia water is introduced through the hollow shaft jand passes into the mass through the ends of the hollow stirrer '8. After the excess acid has been neutralized by ammonia as just described, the mixture of dinitr'ov glycerin, water and nitrate of ammonia is run into a vesseLprovidecl with a. jacket for Warm water circulation. in section such a vessel.

the vessel, m the material in the vessel, n the jacket .havin' the pi es -0 leading to and from said jac et, for t e circulation of warm the vessel to a point at which heat, at a temwater. At the upper portion of the vessel is the pipe leading to a vacuum pump. Heat is applied by causing Warm water to passthrough pi es 0 and jacket n. Vacuum. is also applie to pipe 3) to lower pressure within perature below that which ail'ects the dinitroglycerin, will cause the mixture to boil and the water to the desired extent to pass off through the pi e 10. After this operation, there 18 left in the vessel dinitroglycerin and a concentrated solution of ammonium ni- $18,138. When I use the term vacuum, I intend to' include a partial vacuum.

This operation is carried on until a greater In Fig. 3 is shown In this drawing, Z is proportion of the water is removed. In this condition, due to the different s ecific gravities of the material, there will layers, in one layer of which is the dinitroglycerin and in the other the ammonium nitrate, and these two layers may be readily separated, as is now done.

Having'now fully described'my invention,

be formed what I claim and desire to protect by Letters Patent is:

1'. In the process of nitrating an organic compound with nitric acid alone, the hereinbefore described step of neutralizin cess of nitric acid for the purpose o producing a valuable byproduct, which consists in neutralizing said excess acid with'ammonia.

2. In theprocess of nitrating an'o'rganic compound with nitric acid alone, the hereinbefore described ste of neutralizing the excess nitric acid fort e purpose'of producing a valuable byproduct, which consists in neutralizing said excess acid with ammonia admitted in a comminuted form.

3. In the process of nitrating an organic compound with nitric acid alone, the hereinbefore described step of neutralizing the excess of nitric acid for the purpose of producneutralizing said excess acid with ammonia, and maintain ng the mass, during said neutralization," at a temperature at which the nitrated material will not decompose.

In testimony of which invention, I have hereunto set my hand, at Wilmington, Del, on this 30th day of Au ust, 1907.

. FRAN IS I. DU PONT.

Witnesses:

IRVING Erna, JAMES J. Coorc.

the ex 75 ing a valuable by-product, which consists in 

